<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    
</body>
<script>
    var num=10;
    var str='10';
    //两个等号判断变量里面存储的值是否相等
    //三个等号先判断变量的类型，再判断变量的值，都相同结果为true
    console.log(num===str);
    console.log(num==str);
    var x=3;
    var y=3;
    var z="3";
    alert(x==y);
    alert(x===y);
    alert(x===z);
</script>
</html>